分布式无线通信系统中的自适应调制空时编码技术

Space time coding with adaptive modulation in distributed wireless communication system

考虑了应用线性离散码(linear disperse coding,LDC)的分布式无线通信系统中非等同调制方式的应用策略。在分布式MIMO(Multiple Input Multiple Output)系统中,通过分析大尺度衰落对传统LDC的后验信噪比(post-SNR)分布的影响,提出了一种偏移LDC的发送策略,这种策略可以对每路调制数据在每根发送天线上的功率进行调整。仿真结果表明,所提的偏移LDC方法在分布式无线通信系统的小区边缘优于传统LDC。而在小区中心,移动台距离各基站的大尺度衰落比较均衡,传统LDC方法可以获得更大的分集增益,本文进一步提出在偏移LDC和传统LDC之间进行自适应切换,能够得到更好的性能。

Use of unequal modulation schemes in distributed wireless communication system（DWCS） utilizing linear disperse coding （LDC） is taken into consideration. A transmission scheme called bias-LDC is proposed based on the analysis of the distribution of post-SNR （Signal to Noise Ratio） affected by large scale fading in distributed MIMO systems. This scheme could adjust power for every symbol over each transmission antenna. Simulation results suggest that the proposed method outperforms the traditional LDC in the cell-edge of DWCS. But in center of the cell, the large scale fadings between mobile station and base stations are balanced, and traditional LDC can get larger diversity gain, so we make an adaptive switch between bias-LDC and traditional LDC, and can get better performance.